This invention relates to a device for sealing on multiple items in a wellbore, e.g., drillpipe with umbilical and/or control lines. More specifically, the invention relates to a multiple item sealing packer insert configured to envelop items within a wellbore upon the application of radial pressure.
Currently, there is no effective way of effecting a seal on multiple lines in the wellbore using an annular blowout preventer (xe2x80x9cBOPxe2x80x9d), diverter, or similar oil field service product. Presently, in wellbore situations in which sealing on multiple lines is required, the annular BOP is closed around these items and leakage occurs at the interface between them. The leakage is produced by the pressure differential in which the higher pressure of the wellbore seeps through gaps between the items to reach the lower pressure outside the wellbore. The amount of leakage varies with wellbore pressure and the number, size, and geometry of the items in the wellbore.
The leakage described above is undesirable because it creates a hazard to both workers and the environment. If there are large gaps between items in the wellbore, the leakage may be substantial and, under high pressure, fluid flow could xe2x80x9cjetxe2x80x9d from the BOP and create a hazard on the rig floor. Moreover, the loss of drilling fluid makes it difficult to effectively control wellbore pressure.
The absence of complete control over wellbore pressure can produce dangerous side effects. For example, wells are typically xe2x80x9cshut inxe2x80x9d to prevent a blowout after a gas xe2x80x9ckickxe2x80x9d is detected within the wellbore. The kick is controlled by sealing the annulus of the wellbore and xe2x80x9ccirculating outxe2x80x9d the gas in a controlled process. If gaps exist between multiple items in the wellbore, the pressure integrity of the closed in well could be lost or reduced. In this case, the well control scheme is less effective and fluid that escapes the wellbore under pressure could produce a hazard to workers.
The leakage of wellbore fluids between multiple items can also lead to environmental contamination. Oilfield service and exploration companies take precautions to prevent drilling fluid or xe2x80x9cmudxe2x80x9d from escaping the fluid circulation system at the rig site. Leakage of drilling mud can contaminate the ground around the BOP stack and, as previously mentioned, can contaminate the rig floor. This is a particular problem when oil-based or potentially corrosive muds are used in the drilling process.
Subsea operations present another difficulty. Environmental regulations prevent the uncontrolled release of drilling fluids into the surrounding subsea environment. The penalties for violating these measures are severe and costly cleanups may ensue.
Elastomer sleeves have been used around items in the wellbore such as umbilical or control lines in an attempt to solve the above problem. These sleeves were attached only to auxiliary lines. A problem of using this method is that locating the sleeves in the BOP, diverter, or similar oil field service product is difficult. The nature of BOP operation typically requires immediate action. Therefore, the sleeves would have to be aligned with the BOP at all times so that they would be in place for activation of the BOP.
The present invention provides a means of sealing on multiple items in the wellbore, e.g., a drillpipe with umbilical and control lines. The invention also has a positive locating feature.
In general, a multiple item sealing packing insert for use with oil field service products in a wellbore has a first member comprising a composite material having an elastomer and a structural support material and a second member comprising a composite material having an elastomer and a structural support material. The first member and second member are configured to envelop items in the wellbore with the elastomer upon application of radial pressure.
In accordance with one or more embodiments of the invention, the two members may be configured to fill an area between the items in the wellbore upon application of radial pressure. The structural support material may be a metal or a thermoplastic. The packing insert may either be a separate entity or an integral part of a blowout preventer, a diverter, or a similar structure.